Projection display device with a cooling air fan

Abstract

A projection display device that includes: a light source unit 1 that includes a discharge lamp 2 as a light source; an image formation unit; a projection optical system; and a light source cooling unit that cools the light source unit. The light source unit is disposed so that a lamp axis that connects two discharge electrodes of the discharge lamp is orthogonal to a projecting direction of the projection optical system, and the light source unit includes: a concave mirror 3 ; and a transparent part 4 that covers an opening of the concave mirror. The light source cooling unit includes: a blowing fan that supplies cooling air; a plurality of air blowing ports 6 a and 6 b disposed at the concave mirror or a connecting part that connects the concave mirror and the transparent part; an air duct 9 that connects the air blowing ports and the blowing fan; a branch switching valve 10 a that is disposed in the air duct and switches between a plurality of branch flow paths so as to allow the cooling air to flow therethrough; and a control valve that is provided for each of the air blowing ports and rotated around a supporting axis by the action of gravity depending on a posture of the light source cooling unit, thereby controlling a wind direction so that the cooling air is blown from above the discharge lamp. The top of the light source lamp is cooled effectively regardless of the installation posture of the projection display device.

What is claimed is: 
     
       1. A projection display device comprising: a light source unit that includes a discharge lamp as a light source; an image formation unit; a projection optical system; and a light source cooling unit that cools the light source unit, thereby projecting an image displayed on the image formation unit by using light emitted from the light source unit,
 wherein the light source unit is disposed so that a lamp axis that connects two discharge electrodes of the discharge lamp is orthogonal to a projecting direction of the projection optical system, 
 the light source unit comprises: a concave mirror whose central axis matches the lamp axis and that reflects the light emitted from the discharge lamp; and a transparent part that covers an opening of the concave mirror, and 
 the light source cooling unit comprises: 
 a blowing fan that supplies cooling air; 
 a plurality of air blowing ports disposed in a circumferential portion of the concave mirror or a connecting part that connects the concave mirror and the transparent part, at positions corresponding to directions in which they are orthogonal to each other with the lamp axis as a center when viewed in the lamp axis direction; 
 an air duct that forms a plurality of branch flow paths connecting the air blowing ports and the blowing fan; 
 a branch switching valve that is disposed in the air duct and switches between the branch flow paths so as to allow the cooling air supplied by the blowing fan to flow therethrough; and 
 a plurality of control valves, each of the air blowing ports being provided with one of the control valves, each of the control valves being rotated around a rotation axis that extends in a direction orthogonal or parallel to the lamp axis by the action of gravity depending on a posture of the light source cooling unit, thereby controlling a wind direction so that the cooling air is blown from above the discharge lamp, 
 wherein each of the control valves is formed of an air control baffle that is rotatable around the rotation axis, 
 the branch switching valve operates so as to send an airflow from an entrance of the air duct toward the air blowing port postured in a vertical direction among the air blowing ports disposed orthogonal to each other, while blocking an airflow toward the air blowing port postured in a horizontal direction, and 
 each of the air control baffles is configured such that 
 when the air blowing port postured in a vertical direction is positioned above the discharge lamp, the air control baffle is inclined, so that airflow through the air blowing port flows into the concave mirror in an oblique direction, thereby being blown toward the top of the light source lamp, and 
 when the air blowing port postured in a vertical direction is positioned below the discharge lamp, the air control baffle hangs in a vertically downward direction, so that airflow through the air blowing port is guided in a vertically upward direction and then flows along the shape of the concave mirror, thereby being blown toward the top of the light source lamp. 
 
     
     
       2. The projection display device according to  claim 1 , wherein the air blowing ports are disposed at at least two positions. 
     
     
       3. The projection display device according to  claim 2 , wherein an exhaust port is provided at at least one position substantially opposed to the air blowing ports. 
     
     
       4. The projection display device according to  claim 1  wherein the air control baffle has rotation stop positions in two directions depending on an installation posture of the projection display device. 
     
     
       5. The projection display device according to  claim 4 ,
 wherein the rotation axis of each of the control valves extends in a direction orthogonal to the lamp axis in the vicinity of the opening of the concave mirror, and 
 one of the rotation stop positions of the air control baffle is set so as to guide the cooling air toward a top of the light source lamp depending on the installation posture of the projection display device. 
 
     
     
       6. The projection display device according to  claim 4 , wherein the air control baffle is rotatable around the rotation axis by the action of gravity. 
     
     
       7. The projection display device according to  claim 1 , wherein the branch switching valve is rotated by the action of gravity to switch between the flow paths. 
     
     
       8. The projection display device according to  claim 1 , further comprising a driving circuit that rotates the branch switching valve,
 wherein the driving circuit rotates the branch switching valve to switch between the flow paths based on information on an angle at which the projection display device is installed. 
 
     
     
       9. The projection display device according to  claim 7 , wherein the branch switching valve is symmetrical with respect to a rotation axis and has a weight portion located at a position away from the rotation axis. 
     
     
       10. The projection display device according to  claim 1 , wherein the branch switching valve is provided with respect to each of the flow paths leading to each of the air blowing ports. 
     
     
       11. The projection display device according to  claim 1 ,
 wherein the air blowing ports are disposed in the circumferential portion of the concave mirror or the connecting part at positions corresponding to at least four directions in which they are orthogonal to each other with the lamp axis as a center, 
 the air duct is divided into two branch flow paths, between which the branch switching valve switches so as to allow the cooling air supplied by the blowing fan to flow therethrough, 
 the control valves include first and second control valves disposed in the respective branch flow paths to be switched therebetween, and 
 the cooling air is blown through one of the air blowing ports depending on the posture of the light source cooling unit. 
 
     
     
       12. The projection display device according to  claim 11 ,
 wherein the air duct, in the downstream after being switched by the branch switching valve to one of the branch flow paths in two directions, is formed so as to surround the concave mirror or the connecting part in a circumferential direction, and 
 each of the branch flow paths includes at least two flow paths leading to the air blowing ports disposed in the circumferential direction, and at least one of the flow paths is switched between a mode of blowing the cooling air and a mode of stopping the cooling air by the first control valve or the second control valve. 
 
     
     
       13. The projection display device according to  claim 12 , wherein the first control valve or the second control valve is rotated around the rotation axis in the air duct by the action of gravity so that the cooling air is guided to the air blowing port that is located at the top, among the air blowing ports disposed in the circumferential direction of the concave mirror or the connecting part, when the projection display device is installed. 
     
     
       14. The projection display device according to  claim 12 , wherein the first control valve or the second control valve has a configuration in which a shield the air control baffle is provided on both sides of the rotation axis such that the center of gravity is located to the air blowing port side relative to the rotation axis. 
     
     
       15. The projection display device according to  claim 11 , wherein the branch switching valve is provided at a portion where the one air duct is divided into the two branch flow paths, and moves in the air duct by the action of gravity to block or open one of the branch flow paths. 
     
     
       16. The projection display device according to  claim 14 , wherein the branch switching valve has a columnar or spherical shape. 
     
     
       17. The projection display device according to  claim 11 , wherein the branch switching valve is provided at a portion where the one air duct is divided into the two branch flow paths, and has a cantilever shape with the air control baffle provided on one side of a rotation axis, so as to be rotated in the air duct by the action of gravity to block or open one of the branch flow paths. 
     
     
       18. The projection display device according to  claim 11 , wherein each of the air blowing ports has an air guide plate that guides air toward the discharge lamp. 
     
     
       19. The projection display device according to  claim 1 ,
 wherein the air blowing ports are disposed in the circumferential portion of the concave mirror or the connecting part at positions corresponding to at least four directions in which they are orthogonal to each other with the lamp axis as a center, 
 the air duct is divided into two branch flow paths, and the branch switching valve is formed of first and second branch switching valves, each being rotated around a supporting axis by the action of gravity to switch between the two branch flow paths so as to allow the cooling air supplied by the blowing fan to flow therethrough, and 
 the control valves include first and second control valves disposed in the respective branch flow paths to be switched therebetween. 
 
     
     
       20. The projection display device according to  claim 19 , wherein the first and second branch switching valves are provided at a portion where the one air duct is divided into the two branch flow paths, and disposed on the respective branch flow path sides with a rotation stopper provided therebetween, each having a cantilever shape with a shield plate provided on one side of a supporting axis, so as to be rotated in the air duct by the action of gravity to block or open the branch flow path where it is disposed.